A laser is a device that emits light, or electromagnetic radiation, through a process of optical amplification based on the stimulated emission of photons. The term “laser” was originally an acronym for “Light Amplification by Stimulated Emission of Radiation.”
Lasers are used in thousands of ways in every sector of society, including consumer electronics, information technology, science, medicine, industry, law enforcement, entertainment, construction, and the military.
Typically, lasers are tightly focused to produce a collimated beam of light that creates a single spot of light on any surface that intersects the beam. If the beam of light is reciprocated, or swept back and forth in a linear fashion, a triangular plane of laser light is created by the inclusive angle of the laser's total sweep area, significantly increasing the area of coverage of the laser beam. Rather than a single spot termination, a linear reference is formed on the surface that the laser beam terminates on, at the hypotenuse of the triangular plane formed by the laser's sweep area. This linear reference is the result of the laser's dot image traveling back and forth over the surface in a linear fashion. If the laser's dot image is linearly scanned back and forth at a fast enough rate, the human eye perceives the scanned image as a solid line image.
Uses of the triangular plane may include scanning the laser vertically across a series of horizontally mounted sensors to determine deviation from a straight line between two distant points. In the construction or building industry, the feedback from the sensors may be used to keep machinery or equipment traveling in a “perfectly” straight line from point “A” to point “B”, correcting for any left or right deviation along the way. This is one of the primary applications for the present invention. The triangular plane may also be used for leveling or grading applications such as agricultural field leveling, construction, or highway maintenance. Other uses of the triangular plane may include point cloud scanning A triangular plane created by a reciprocating laser may be used instead of the X & Y mirrors and galvanometers to reduce cost.
Regarding uses of the line image, one of the oldest known uses for the laser line termination is the bar code scanner. The scanned line image formed could also be used as a straight line reference for alignment of material, machinery, tools and other applications in assembly and manufacturing applications.
In addition to lines formed by reciprocating the laser beam, line images are also created optically. One of the advantages of a reciprocating line image is that it is typically brighter and more visible (depending on the rate of the scan, sweep, or reciprocation) than line images formed with optics, due to the absorption and reflection loss created from the optical line lenses. Other uses for laser line images as guidelines are numerous, and include everything from painting stripes on airplanes to alignment of logs before they are cut at a sawmill, and many others.
Several references disclose devices and methods that create a triangular plane of light and/or a laser line termination. Typically, these references disclose a device for actuating the laser back and forth or tilting a mirror back and forth, which in turn causes the laser beam to sweep. For example, U.S. Pat. No. 5,691,535 uses two moveable mirrors for laser scanning systems, which create a light beam, directed along a path to a stationary mirror element. The light beam is focused by a lens and directed by a first moveable mirror and a second moveable mirror, which each are coupled to galvanometers. The galvanometers, which are controlled by electronic controllers, use the mirrors to deflect the light beam, as it scans surfaces in a “bow-tie” pattern.
Similarly, U.S. Published Patent Application No. 2010/0256940 also employs a laser scanning system with mirrors. The laser scanning system includes a laser light source, a mirror, a distance measuring unit, and a control unit. The laser light source projects the light beam into a minor which then deflects the beam for scanning. The distancing measuring unit calculates the distance of an object by detecting the light quantity of the reflected laser beam as received while the control unit drives and controls both the light source and distance measuring unit.
Despite the various structures and configurations, most laser scanning systems use mirrors to deflect the light beam to create the triangular plane. This was preferred because it was believed that moving non-minor components was impractical. However, minor movements are not always desirable in every application.
Regarding references that disclose the movement of the laser component, rather than a minor component, U.S. Pat. Nos. 5,144,120, 5,254,844, 5,583,332, 5,907,145, and 5,525,791, all issued to Krichever, discloses various embodiments of a mirrorless scanner with a movable laser light source. The Krichever mirrorless laser scanner is a hand-held barcode scanning system that includes a laser light source component mounted on a shaft, which is attached to a motor or actuator. The motor provides repetitive twisting movements. The problem with the Krichever mirrorless laser scanners is that the back and forth twisting movements of the motor are very inefficient, require a significant power source, and quickly burn out the motor. The motor burns out quickly because the twisting movement is not a natural movement for a motor. Furthermore, this causes problems with excessive torque produced from changing directions.
Therefore, what is needed is a laser scanning device with a robust laser light source which reciprocates or sweeps a laser light beam efficiently without undue stress on the laser light source or the reciprocation motor.